Method and device for manufacturing laboratory articles such as samples of paper sheets



Oct. 5, 1965 e. GRAUSS ETAL 3,210,241

METHOD AND DEVICE FOR MANUFACTURING LABORATORY ARTICLES SUCH AS SAMPLES OF PAPER SHEETS 2 Sheets-Sheet 1 Filed May 8, 1963 vlllllllllllllllll Oct. 5, 1965 G. GRAUSS ETAL 3,210,241

METHOD AND DEVICE FOR MANUFACTURING LABORATORY ARTICLES SUCH AS SAMPLES OF PAPER SHEETS United States Patent 3,210,241 METHOD AND DEVICE FOR MANUFACTURTNG LABORATORY ARTICLES SUCH AS SAMPLES OF PAPER SHEETS Georges Granss, Paris, Georges Sauret, Epinay-sur-Orge, and Guy Jacqueiin, Grenoble, France, assignors to Etablissements Georges Grauss and Centre Technique de llndustrie des Papiers, Cartons et Cellulose, Paris, France Filed May 8,1963, Ser. No. 278,900 Claims priority, application France, May 16, 1962, 897,678 11 Claims. (Cl. 162218) Various processes and devices are already known for the manufacture in the laboratory of forms, or samples of sheets of paper, which Will enable the properties of the papers and paper pulps to be examined and the characteristics for industrial manufacture to be more accurately determined.

However, forms are manufactured in a static manner in the laboratory and the paper is consequently isotropic throughout its plane. However, in the course of industrial manufacture, in view of the rotation of the machines, a preferred orientation of the fibres occurs and the result is anisotropy of the paper. This being so, the differences in structure which exist between paper manufactured in the laboratory and industrially manufactured paper lead to certain difficulties in the interpretation and the application of the results of the experiments.

It is an object of the invention to provide a new process for the manufacture of paper forms in the laboratory, enabling a structure completely analogous to that obtained industrially to be given to the experimental paper.

According to a first feature of the invention, the paper pulp is projected Onto the inner surface of a surface of revolution which is preferably cylindrical and which is rotated about its axis. The paper pulp is projected chiefly but not exclusively by centrifugal force which applies the paper pulp over the inner surface of the surface of revolution.

According to another feature of the invention, a fluid film is maintained over the said inner surface of the sur face of revolution, the said film being a film of water, for example, and intended to maintain the homogeneity of the paper pulp whilst it is centrifuged. Indeed, it has been observed that the thinner the fluid film, the more the fibres are drawn out under the effect of the centrifugal force, this drawing out being at its maximum in the total absence of the fiuid film. By means of the invention, it is therefore possible to carry out experiments on the manufacture of paper from pulps of various different fluidities.

It is another object of the invention to provide a device to carry out the process referred to. This device comprises a cylindrical drum rotated about its central longitudinal axis and preferably arranged vertically, said drum having a sealed lower end. The drum is provided on the inside with a coaxially arranged cylindrical filtering wall, and the upper surface of the drum is provided with 21 preferably annular lid of which the inner diameter is in all cases less than the diameter of the filtering wall.

Advantageously, at least one small hole is provided in the lid of the drum and the distance between it and the axis of rotation of the drum is slightly less than the radius of the filtering wall, this dimensional difference constituting a value corresponding to the thickness of the fluid film required on the inner surface of the filtering wall.

It will, therefore, be seen that the thickness of the film of Water which is to be maintained on the inner surface of the filtering wall while the paper pulp is centrifuged may thus be varied at will during successive experiments.

If desired however the annular drum lid may have no holes, the inner diameter of the said lid then being slightly less than the diameter of the inner surface of the filtering wall, this difference being a value corresponding to the thickness of the fluid film required on the said inner surface.

The paper pulp may be applied on the inner surface of the filtering wall in any one of a number of Ways. For instance, a certain quantity of paper pulp may be arranged at the bottom of the drum and driven onto the inner surface of the filtering wall and uniformly distributed over it during the rotation of the drum. However, it seems to be more advantageous to provide a system for projecting the said paper pulp.

An arrangement for projecting the paper pulp onto the inner surface of the filtering wall may be constituted by a tube free to move parallel to the axis of rotation of the drum. During the rotation of the drum, the end of the aforementioned tube effects a to-and-fro movement over the entire height of the inner surface of the filtering wall and thus ensures a uniform projection of paper pulp.

Alternatively, the projection arrangement may be in the form of a plurality of fixed tubes (preferably distributed in a regular manner) over the entire height of the filtering wall.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings which show two embodiments thereof by way of example, and in which:

FIGURE 1 shows an axial section through a first embodiment of a device according to the invention, and

FIGURE 2 shows an axial section through a second embodiment thereof.

Referring to the drawings, the side wall 1 of a cylindrical drum is fixed to the base 2 thereof, said base being appropriately shaped and adapted to be secured to the end of a shaft 3 rotatable by a motor (not shown). The cylindrical wall 1 and the base 2 of the drum are dynamically balanced so that the entire arrangement may be rotated without any risk of vibration.

A cylindrical filtering Wall designated by the general reference 4 is arranged coaxially with the drum wall 1. This filtering wall is preferably constituted by a rigid support 5, which may, for example, be made of perforated sheet metal. A sheet 6 with a wide mesh and a sheet 7 with a fine mesh are arranged on the inner surface of the support 5. These sheets may be made of any appropriate material, such as metal, cloth or a plastics material, for example.

The lower end of the filtering wall 4 is engaged in a circular groove 2a provided in the base 2 of the drum and it is wedged and gripped therein by any appropriate means, as a cylindrical chock or wedge 8.

The filtering wall 4 is fixed at its upper end to an annular flange 9 which has a series of holes 9a arranged above the annular space 10 between the filtering wall 4 and the side wall 1 of the drum. The outer periphery 9b of the flange 9 rests on the side wall 1 of the drum and is held in position by a movable lid '11 provided with a shoulder 11a bearing on the flange 9. The lid 11 may be screwed onto the side wall 1 of the drum or secured to it by any other appropriate means so that it may easily be dismantled.

The annular lid 11 is perforated at a number of places 11b, the holes being preferably small, and which are evenly distributed around a circle of which the centre is the axis of rotation of the drum. The distance between the axis of rotation and the radially outermost points of holes 11b is slightly less than the radius of the filtering wall 4, and this dimensional difference constitutes a value e corresponding to the thickness of the film of water it is The machine is further provided with means for the application and removal of the fluid, which may, for example, be water, via a delivery pipe 12 and a suction pipe 13, which may, for example, be of the type described in the French Patent No. 1,142,737 filed on February 17, 1956 by Georges Grauss and entitled Self-Draining Centrifuge-Filter. The said suction pipe may be mounted free to move radially in an adjustable manner. In any case the end 13a must be able to penetrate into the lid 11 at a distance from the axis of rotation of the drum which may be considerably greater than the radius of the filtering wall 4.

In the embodiment of FIGURE 1, the means for supplying the paper pulp comprises a tube 14, preferably bent at its lower end towards the filtering wall 4 and capable of being moved to-and-fro in the directions indicated by the arrows F and F, parallel to the axis of rotation of the drum. The mechanism enabling this to-and-fro movement of the tube 14 to be effected has not been shown, but any known reciprocating mechanism may be used to this end.

An alternative arrangement for supplying the paper pulp has been shown in FIGURE 2, and comprises a plurality of fixed tubes 15. These tubes are regularly distributed over the entire height of the filtering wall and may be supplied by a single conduit 16 or by a number of conduits leading from a common reservoir.

The arrangement operates as follows. According to a first practical method of applying the process, a certain quantity of paper pulp is arranged on the base 2 in the bottom of the drum so that it is projected under the effect of centrifugal force on rotation of the drum, onto the filtering wall 4. Thus, the pipe 14 of FIGURE 1 or the pipes 15 and conduit 16 of FIGURE 2, are not used. The water, and the fluid contained in the paper pulp, will pass through the filtering wall and will be evenly distributed over the side surface 1 of the drum. It will then 'be removed by the suction pipe 13.

When the sheet of paper which has formed on the inner sheet 7 of the filtering wall 4 is deemed to be sufficiently dried, the machine is stopped. All that remains in order to remove the sheet of paper is to remove the lid 11 and to withdraw the assembly of the flange 9 and the filtering wall 4. The sheet of paper may then easily be withdrawn from its support.

In another application of the process, the paper pulp is actually projected onto the filtering surface 4 by means of a projection arrangement constituted either by the tube 14 (FIGURE 1) or by the assembly of tubes 15 and conduit 16 (FIGURE 2) during rotation of the drum. The rest of the operation is carried out in the manner just described.

However, in some cases, it may be advantageous to project the paper pulp onto the filtering wall 4 while a certain film of water or appropriate fluid, having a thickness e, is maintained on the latter. To this end, the said fluid is first of all passed into the drum by means of a tube 12, while the drum is rotated, the end of the suction pipe 13, being, of course, located at a distance from the axis of rotation which is smaller than the diameter of the desired fluid cylinder. The fluid spreads out evenly in the annular space and passes through the filtering wall 4- until it constitutes a vertical wall of which the thickness is determined by the position of the holes 11b or of the inner diameter 11c of the lid. Under these conditions, a fluid film having a thickness e is constantly maintained over the inner surface of the filtering wall 4. It should however be noted that the thickness e of the fluid film may also be determined by the judicious regulation of the radial position of the suction pipe 13.

The paper pulp is then projected, preferably by means of either one of the two supply systems which have already been described. When a sufficient quantity of paper pulp has been distributed over the cloth 7, the supply of paper pulp is shut off and the water contained in the annular space 10 is evacuated by means of suction pipe 13 which is then located in its extreme radial position. The rest of the operation is then carried out in the manner already described.

By means of the device and the process in accordance with the invention, it is possible to manufacture paper sheets in the laboratory in a manner completely analogous to industrial conditions, but at the same time allowing for a wide variety of experiments, owing to the various different possibilities of the apparatus which has just been described.

It will be apparent that the invention has only been described by way of example, and that various modifications may be made to the specific details referred to, without in any way departing from its scope.

We claim:

1. In the process of manufacturing samples of sheets of paper in the laboratory by centrifugal forming on a rotating cylindrical surface, the steps comprising, in the order recited: rotating said cylindrical surface about its longitudinal axis; forming a fluid film over the inner face of said cylindrical surface; projecting paper pulp onto said inner face while maintaining said film at least until said projection has been terminated.

2. A process as recited in claim 11, comprising in the order recited, the further steps of: terminating said projecting operation when the desired quantity of pulp has been projected; withdrawing said fluid film; and stopping the rotation of said surface when said pulp has attained the desired degree of dryness.

3. A process as recited in claim 1, wherein said fluid film comprises water.

4. A device for manufacturing samples of sheets of paper, in the laboratory, comprising a cylindrical drum having a continuous, fluid-tight cylindrical wall, said drum also having one of its ends sealed, means for rotating said drum about its central longitudinal axis, a cylindrical filtering wall arranged coaxially with and inside said drum, an annular lid covering the other end of said drum and having an inner diameter and an outer diameter, said inner diameter of said lid being less than the diameter of said filtering wall.

'5. A device as set forth in claim 4, in which said lid is ape-rtured, the distance between the radially outermost point of said aperture and the axis of rotation of said drum being slightly less than the radius of said filtering Wall, this dimensional difference constituting 'a value corresponding to the thickness of a fluid film to be applied over the inner surface of said filtering wall.

6. A device as set forth in claim 4, in which said inner diameter is slightly less than the diameter of the inner surface of the filtering wall, this dimensional difference constituting a value corresponding to the thickness of a [fluid film required to be applied over the inner surface of said filtering wall.

7. A device for manufacturing samples of sheets of paper, in the laboratory, comprising a cylindrical drum having a continuous, fluid-tight cylindrical wall, said drum also having one of its ends sealed, means for rotating said drum about its central longitudinal axis, a cylindrical filtering wall arranged coaxia'lly with and inside said drum, a lid covering the other end of said drum and having an inner diameter and an outer diameter, said inner diameter of said lid being less than the diameter of said filtering wall, and a suction pipe located inside said lid and mounted so as to be free to move radially and being capable of being fixed in an adjustable manner.

8. A device for manufacturing samples of sheets of paper, in the laboratory, comprising a cylindrical drum having a continuous, fluid-tight cylindrical wall, said drum also having one of its ends sealed, means for rotating said drum about its central longitudinal axis, a cylindrical tfiltering wall arranged co'axially with and inside said drum, a lid covering the other end of said drum and having an inner diameter and an outer diameter, said inner diameter of said lid being less than the diameter of said filtering Wall, and an arrangement for projectingpaper pulp onto the inner surface of said filtering wall, said arrangement comprising a tube free to move parallel to the axis of rotation of said drum.

9. A device for manufacturing samples of sheets of paper, in the laboratory, comprising a cylindrical drurn' having a continuous, tfluid-tight cylindrical wall, said drum also having one of its ends sealed, means for rotating said drum about its central longitudinal axis, a cylindrical filtering Wall arranged coaxially with and inside said drum, a lid covering the other end of said drum and having an inner diameter and an outer diameter, said inner diameter of said lid being less than the diameter of said filtering Wall, and an arrangement for projection of paper pulp onto the inner surface of said filtering wall, said arrangement comprising a plurality of fixed tubes radially branching from a conduit located parallel to the axis of rotation of said drum.

10. A device for manufacturing samples of sheets of paper, in the laboratory, comprising a cylindrical drum having a continuous, fluid-tight cylindrical Wall, said drum also having one of its ends sealed, means for rota-ting said drum about its central longitudinal axis, a cylindrical filtering -wa.ll arranged coaXially with and inside said drum, a lid covering the other end :of said drum and having an inner diameter and an outer diameter, said inner diameter of said lid being less than the diameter of said filtering wall, said filtering wall comprising a rigid external perforated support, an internal sheet of a material having a fine mesh, and an intermediate sheet of material having a large mesh located between said rigid support and said inner sheet.

-1 1. A device for manufacturing samples of sheets of paper, in the laboratory, comprising a cylindrical drum having a continuous, fluid-tight cylindrical wall, said drum also having one of its ends sealed, means for rotating said dru-m about its central longitudinal axis, a cylindrical [filtering wall arranged coaxially with and inside said drum, a lid covering the other end of said drum and having an inner diameter and an outer diameter, said inner diameter of said lid being less than the diameter of said filtering Wall, said filtering wall being removable.

References Cited by the Examiner UNITED STATES PATENTS 768,3 06 8/ 0'4 River 1 6 221 8 1,53 1,482 3/25' Hang 1 62295 1,819,771 8/ 31 Darrah 1 622l8 FOREIGN PATENTS 981,228 1/61 France.

242, 172 9/ 46 Switzerland.

DONA LL H. SY'LVESTER, Primary Examiner. 

1. IN THE PROCESS OF MANUFACTURING SAMPLES OF SHEETS OF PAPER IN THE LABORATORY BY CENTRIFUGAL FORMING ON A ROTATING CYLINDRICAL SURFACE, THE STEPS COMPRISING, IN THE ORDER RECITED: ROTATING SAID CYLINDRICAL SURFACE ABOUT ITS LONGITUDINAL AXIS; FORMING A FLUID FILM OVER THE INNER FACE OF SAID CYLINDRICAL SURFACE; PROJECTING PAPER PULP ONTO SAID INNER FACE WHILE MAINTAINING SAID FILM AT LEAST UNTIL SAID PROJECTION HAS BEEN TERMINATED.
 4. A DEVICE FOR MANUFACTURING SAMPLES OF SHEETS OF PAPER, IN THE LABORATORY, COMPRISING A CYLINDRICAL DRUM HAVING A CONTINUOUS, FLUID-TIGHT CYLINDRICAL WALL, SAID DRUM ALSO HAVING ONE OF ITS ENDS SEALED, MEANS FOR ROTAT- 